Ronybuy Fuel Pump Relay Kit 12V 40A P/N 30247 — Waterproof Heavy‑Duty Wiring Harness

Ronybuy's 12V 40A electric fuel pump relay kit (P/N 30247) is a waterproof, heavy‑duty wiring harness that routes battery power through a 40A relay and 30A inline fuse to protect and boost fuel pump performance.

This relay harness replaces OEM part number 30247 and gives you a reliable way to power an electric fuel pump from the battery rather than drawing heavy current through the vehicle’s factory wiring. The kit includes a prewired relay base, inline waterproof fuse holder, heavy gauge power leads, and mounting hardware so you can create a cleaner, safer power feed that reduces voltage drop and prevents overload of original circuits.

How does the Ronybuy kit improve fuel pump electrical performance?

By moving the high current path directly to the battery, the relay kit reduces voltage loss and heat in the stock wiring. The relay is triggered by the factory 12V pump signal but supplies pump current through a dedicated 10‑gauge feed, improving pump voltage under load.

• 40A heavy duty relay handles larger pump draws safely
• 10 ft 10‑gauge red battery feed minimizes voltage drop
• 6 ft 10‑gauge orange pump lead provides a direct high‑current path
• 30A inline waterproof fuse protects the new power circuit

What’s included and how easy is installation?

The kit ships with everything needed for a plug‑and‑play bypass wiring setup and comes with a wiring diagram for step‑by‑step guidance. Color‑coded wires and preassembled relay base simplify connections so you can complete the job with basic tools.

• 1× 40A waterproof relay and relay base with harness
• Inline waterproof fuse holder and 30A fuse installed
• Premeasured leads: 10 ft red, 6 ft orange, 2 ft brown trigger, 4 ft black ground
• Mount screws, heat‑shrink ring terminals, wire connectors, cable ties and diagram

Will this relay kit work with my vehicle or pump?

This universal 12V relay harness is designed to replace OEM P/N 30247 and fits most 12V electric fuel pump systems that draw up to 40 amps. It’s suitable for stock and many aftermarket pumps provided the pump’s continuous current does not exceed the relay rating.

• Compatible with 12V systems and OEM 30247 applications
• Use if pump current is ≤ 40A; fuse provides 30A over‑current protection
• Ideal for boats, cars, trucks, and custom fuel setups requiring relay bypass
• Not recommended for pumps exceeding the relay amperage rating

How durable is the kit for harsh environments?

The relay and inline fuse holder are built to resist moisture and heat, and the heavy‑gauge wiring is intended for long service life in demanding conditions. Heat‑shrink connectors and included cable ties help secure and weatherproof key junctions.

• Waterproof relay housing and inline fuse holder for protection
• Heavy gauge 10AWG wiring for higher current capacity and less heat
• Heat‑shrink terminals and connectors for sealed electrical joints
• Includes mounting screws and ties for secure installation

Who is this for? The Ronybuy 12V 40A fuel pump relay kit is aimed at DIY mechanics, performance tuners, restorers, and technicians who need a safe, robust solution to supply direct battery power to an electric fuel pump. Choose this kit if you want to reduce voltage drop, protect factory wiring from overload, and install a weatherproof relay harness that matches OEM P/N 30247. It’s a practical upgrade for vehicles and custom builds using 12V pumps within the kit’s electrical ratings.